The Coastline Is Retreating. Should the Montauk Lighthouse Stand Its Ground?

Lighthouses speak to the imagination. They illuminate the darkness, remind us of a vanishing maritime heritage and embody what it means to make it safely home.

So when erosion threatens to send a lighthouse toppling into the sea, people want to save it. But how? The way we answer that question involves more than engineering. It can become a statement about how we intend to live with our eroding coasts.

In 1796, when the Montauk Lighthouse was built on a bluff on the east end of Long Island, it was 300 feet or so from the cliff edge. Today it stands about 75 feet from the edge, and the Army Corps of Engineers is proposing to prevent further erosion by installing a rugged 840-foot rock revetment at the toe of the bluff. An organization of surfers is challenging the plan, saying it will spoil some of the best surfing spots on Long Island.

But the Montauk debate is about more than surf.

Protecting a lighthouse with rocks, concrete or other coastal armor can symbolize a determination to hold the line, to defy nature and to do what it takes to protect coastal structures from the sea. The armor proposed at Montauk “is a proven technology,” said Henry Bokuniewicz, an oceanographer at the State University at Stony Brook who studies coastal processes.

The lighthouse could also be protected by moving it back from the cliff edge, an action with very different symbolic value. In an era of rising seas, accelerating erosion and increasing storm threats, moving the Montauk Lighthouse would send a powerful signal that it is time to consider retreating from the coast. “It would be a heck of a good example” for coastal managers, said Orrin H. Pilkey Jr., emeritus director of the Duke University Program for the Study of Developed Shorelines.

And it could be done, according to Joe Jakubik, project manager for International Chimney, a company based in Buffalo. The company has done repair work on the Montauk Lighthouse and has moved others up and down the coast, including the Cape Hatteras Lighthouse, the nation’s tallest, which it moved 1,500 feet inland in 1999.

Photo

Credit
Lisa Haney

Moving the Montauk Lighthouse would present its own problems, Mr. Jakubik said, but “is it technically feasible? Yes.”

There is a choice to be made. Is Montauk a place to hold the line or a place to retreat? As with armor projects elsewhere on the coast, the answer may hinge on the project’s effects not where it might be built, but at beaches downdrift, in this case, beaches to the west.

On most ocean coasts, currents constantly move sand along the beach. As sand erodes, currents carry new sand in to replace it. The amount of sand varies from place to place, but coastal scientists estimate that at places like Fire Island as much at 600,000 cubic yards of sand move along the beach each year. The question is, how much of it comes from erosion of the Montauk bluffs?

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Estimates “pretty much range all over the place,” Dr. Bokuniewicz said. His best estimate was 8,000 to 25,000 cubic yards, an amount he characterized as “negligible.”

Anyway, the Montauk bluffs are made up of whatever the glaciers left behind when they began retreating from what is now Long Island, about 15,000 years ago. “It tends to be glacial till” and not much good for beach-building, said Norbert Psuty, a coastal scientist at the Institute of Marine and Coastal Sciences at Rutgers. “There is a lot of it, but it’s loose and it really does not stand up to wave attack.” But S. Jeffress Williams, a coastal geologist with the United States Geological Survey who has studied the Long Island coast, said he thought a third or more of the sand moving along the south coast might come from Montauk bluffs. Given that the Corps of Engineers is chronically battling to keep sand on erosion-prone Long Island beaches, Dr. Williams said, “you want to reduce anything you do to armor the beach that is going to result in reduced sediment supply to beaches downdrift.”

If he is right, the Montauk Lighthouse is a good example of a phenomenon that is all too common on the coast: armoring a building or road or other infrastructure in one place at the cost of environmental damage someplace else.

As Dr. Psuty put it, armor or no armor, “the Montauk Lighthouse is on a cliff, and the cliff by virtue of being a cliff is an erosional location.” Maybe, he said, “there should be an attempt to safeguard the structure, the symbolism of the structure, and move it away from the hazard that it is facing, which is erosion.”

Given his doubts about the bluff as a sand source, Dr. Bokuniewicz does not agree. But even he adds a cautionary note: “It would be a mistake to think that if they armor Montauk Point it is a policy that should be adopted everywhere.”

A version of this article appears in print on , on Page F3 of the New York edition with the headline: The Coastline Is Retreating. Should the Montauk Lighthouse Stand Its Ground?. Order Reprints|Today's Paper|Subscribe